脑血流储备功能的多模态影像评估技术研究

颅内动脉粥样硬化是我国缺血性卒中的主要病因类型。目前颅内动脉的评估仅依靠解剖学狭窄程度，无法衡量血流动力学变化和侧支循环的影响，导致治疗适应证不明确，卒中复发率高。我们率先将压力导丝技术用于评估颅内动脉狭窄的血流动力学，首次测量出脑血管的血流储备分数（FFR），论证了介入治疗对FFR的改善作用。我们还研发了利用DSA影像测算FFR的方法。基于此，我们拟通过压力导丝测算FFR，研究血管激发试验在脑血管FFR评估中的作用，明确激发态FFR与侧支循环的关系；进而研发基于CTA/MRA及DSA影像的快速FFR评估技术，比较其与压力导丝测量FFR的一致性；最后评估FFR对症状性颅内动脉狭窄患者血管学事件的预测价值，确立FFR反映功能性狭窄的截断值；这一课题，旨在建立颅内动脉狭窄全新的评估模式和简便的技术平台，为优化脑梗死的防治策略提供循证医学依据。

Intracranial atherosclerosis is a major cause of ischemic stroke in China. The current evaluations of intracranial atherosclerosis depend on the anatomical stenosis degree. Previous CTA, MRA, and DSA methods can not reveal the hemodynamic features of the intracranial arteries, thereby limiting the clinical efficacy of endovascular strategy of intracranial stenosis. To this end, we first utilized pressure guide wire to evaluate the fractional flow reserve (FFR) of intracranial stenosis. We found the endovascular strategy could significantly improve the FFR of intracranial stenosis. We also established a CFD model to generate an indirect FFR value from DSA imaging data. Based on these findings, we aim to further measure FFR using pressure guide wire technique, and study the role of provocation test in the intracranial FFR evaluation. We also compared provoked FFR value with resting FFR and collateral circulation. We next establish an indirect method to evaluate FFR based on CTA/MRA or DSA imaging data, and examine its consistency with FFR based on pressure guide wire. We then examined FFR for its potential influence of natural outcome or the endovascular prognosis of symptomatic intracranial stenosis cohort patients. This study is to provide a novel model and convenient platform for intracranial atherosclerosis evaluation, thus providing clinical evidence for the prevention of ischemic stroke.